textproduct: Quad Cities

KEY MESSAGES

- Freezing rain possible this evening, mainly along/north of Highway 20.

- Windy conditions tonight/Wednesday with peak gusts between 45-55 mph. A period of light snow and even some heavier snow showers may accompany the strong winds leading to reductions in visibility.

- Additional clipper systems will likely result in periods of accumulating snow Thursday through Sunday.

- Temperatures will drop for the weekend with wind chills well below zero Friday and Saturday night.

SHORT TERM /THROUGH WEDNESDAY/

Issued at 230 PM CST Tue Dec 9 2025

This Evening into Early Tonight: SPC mesoanalysis had a strong surface low over eastern North Dakota with mild southerly flow downstream across portions of the Midwest, including Iowa and Illinois. Locally, the freezing line has made it up to the Highway 30 corridor with temperatures in the lower 30s north to mid 30s - near 40s south. Warm air advection will continue into this evening and tonight with steady SW to W surface winds. Therefore, anticipate all locations to eventually rise above freezing and hold in the 30s and 40s until a strong cold front comes rushing through the area late tonight. Have maintained the Winter Weather Advisory for the counties along/north of Highway 30 with the surface wet-bulb 32 F isotherm set up a bit further south than the ambient temperature. It does appear that the most likely area for a brief window of freezing rain is along/north of the Highway 20 corridor where the surface wet- bulb may not warm above freezing until closer to 9 PM tonight.

Late Tonight into Wednesday: As the surface low tracks into Lower Michigan and deepens to around 988mb, it will drag a strong cold front through the region leading to very windy conditions with a tight pressure gradient over the area. Momentum transfer supports widespread gusts between 40 to 50 mph, with some potential for 55+ mph favored west and southwest of the Quad Cities. While it does look like there will be an area of wrap around light snow late tonight into early Wednesday morning, sweeping from north to south through parts of the area, there is also potential for moderate to heavy snow showers along the front. Confidence is low on the heavier snow shower/squall scenario with recent hi-res models backing off a bit. With that said, the ingredients are supportive with low values of SBCAPE and decent low-level saturation, so definitely something to monitor closely.

Another potential impact late tonight through early Wednesday AM is for blowing and drifting snow in open and rural areas, which would be favored north of I-80 in Iowa where there is a deeper snowpack and temperatures will not be above freezing as long as other locations to the east/south. There is uncertainty with how impactful the blowing snow will be due to melting today into tonight ahead of the cold front. But with such strong winds expected, thought it was prudent to extend the Winter Weather Advisory through mid morning on Wednesday to account for the potential visibility reductions from either some falling snow and/or blowing snow. A Wind Advisory is in effect south of Highway 30, but even in this area there may be a period of reduced visibilities from falling and/or blowing snow early Wednesday morning which could impact the morning commute. Patchy light snow and flurries may linger through Wednesday afternoon as winds decrease significantly with temps holding in the 20s and 30s.

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/

Issued at 230 PM CST Tue Dec 9 2025

The pattern looks to remain active with a couple of clipper systems progged to cross the region, primarily for the Thursday night and Saturday time frames. Additionally, a very cold weekend is likely, with Saturday night/Sunday morning potentially bitterly cold.

First, let's discuss the clippers. The first is progged to come through Thursday night, driven by 850-700 mb layer warm air advection/frontogenetic forcing. Precipitation types appear to be largely snow in our CWA, although there is a noticeable warm nose aloft around the 700-800 mb layer in the NAM/GFS soundings over our southern counties, which could support a wintry mix. Where snow is expected, this clipper could bring a few inches of new snow accumulation, given NBM probabilities of two inches of snow or greater is around 40-60%, particularly over northwestern Illinois into northeastern Iowa. The character of the snow appears to be more of a slightly drier snow to the northeast (snow ratios of 13-15:1) compared to farther southwest, where a wetter snow is more likely (snow ratios 7-10:1). Precipitation should be mostly over by sunrise Friday morning, with high pressure gradually nosing into the region through the day. A much colder air mass is expected to move into the region Friday night, right before the second clipper moves across the area Saturday. Friday night low temperatures look to fall to the single digits above zero for most locations. Due to the colder air mass in place, p-types are expected to be entirely snow, and pretty dry and fluffy snow at that. LREF ensemble mean soundings shows a deep thermal profile (from the surface up to around 700 to 600 mb) firmly within the DGZ, which supports a dry, fluffy snow character. Snow ratios of 15-19:1 are very much on the table, but with a weak signal for snow, it appears that blowing snow isn't going to be much of an issue. The second clipper appears to have a weaker signal for snow accumulations compared to the first, with NBM probs of two inches only around 30-50%.

In the wake of the second clipper system, an arctic air mass builds in for Saturday night into Sunday morning. Both the GEFS and ECMWF ensembles for 850 mb temperatures suggest magnitudes around 12 to 16 degrees C below zero, which would be some of the coldest air yet this season. These 850 temperatures would be near the daily minimum for December 14th at 12z (6 AM) per SPC sounding climatology, so a very cold air mass for this time of the year. Northwest winds look to stay elevated enough to combine with negative single digit and lower teens low temperatures to support widespread wind chill values of -15 to -30 degrees for most of the CWA Sunday morning. LREF exceedance probabilities of wind chills 20 degrees below zero or colder is around 50-80% for locations along and north of Interstate 80, so a pretty strong signal for a bitterly cold morning. Cold weather headlines are likely needed, if these trends continue. After Sunday, temperatures look to gradually warm as southerly return flow around the departing high should moderate temperatures into the early portions of next week.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1158 AM CST Tue Dec 9 2025

Active weather expected in this TAF period with strong winds, LLWS, periods of light precipitation and low clouds. Light freezing rain is possible this evening, mainly at DBQ with temperatures initially around freezing before warming into tonight. A strong area of low pressure will pass to the north across Wisconsin tonight and bring a cold front through the area, leading to very strong WNW to NW winds up to 35 - 45 kts into Wednesday AM. The gusty winds will likely be accompanied by a period of either snow showers or a steadier light snow, resulting in visibility reductions to MVFR/IFR; expect prevailing MVFR ceilings at all the terminals later tonight into Wednesday AM, and IFR possible at DBQ. Additionally, blowing snow could become a concern at CID with low confidence on the impact to visibility at this time.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Winter Weather Advisory from 6 PM this evening to 9 AM CST Wednesday for IAZ040>042-051>054. Wind Advisory from midnight tonight to 9 AM CST Wednesday for IAZ063>068-076>078-087>089-098-099. IL...Winter Weather Advisory from 6 PM this evening to 9 AM CST Wednesday for ILZ001-002-007. Wind Advisory from midnight tonight to 9 AM CST Wednesday for ILZ009-015>018-024>026-034-035. MO...Wind Advisory from midnight tonight to 9 AM CST Wednesday for MOZ009-010.